package dp;

/**
 * Created with IntelliJ IDEA.
 * Description: 509. 斐波那契数
 * User: Li_yizYa
 * Date: 2025/7/1
 * Time: 8:42
 */
public class Solution1 {
    /**
     * dp
     * @param n
     * @return
     */
    public int fib1(int n) {
        if (n <= 1) {
            return n;
        }
        int[] dp = new int[n + 1];
        dp[0] = 0;
        dp[1] = 1;
        for (int i = 2; i <= n; i++) {
            dp[i] = dp[i - 1] + dp[i - 2];
        }
        return dp[n];
    }

    /**
     * 递归
     * @param n
     * @return
     */
    public int fib(int n) {
        if (n <= 1) {
            return n;
        }
        return fib(n - 1) + fib(n - 2);
    }
}
